Hybrid shelf with embedded thermal spreader

ABSTRACT

A refrigerated merchandiser including a case defining a product display area and including an air inlet and an air outlet in communication with the product display area to form an air curtain across a front of the product display area. The refrigerated merchandiser also includes a shelf that is coupled to the case within the product display area. The shelf includes insulation between a top and a bottom of the shelf, and a passive heat exchanger that has a heat pipe embedded in the shelf within the insulation and that extends from a front of the shelf to a back of the shelf. Ambient air infiltrating the air curtain initiates passive heat transfer within the plurality of heat tubes.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of and priority to U.S. ProvisionalPatent Application No. 63/300,977, filed on Jan. 19, 2022, the entirecontents of which are hereby incorporated by reference.

BACKGROUND

The present invention relates to refrigerated merchandisers, and moreparticularly to refrigerated merchandisers including open commercialrefrigerated merchandisers.

Refrigerated merchandisers are typically used in retail food storesettings such as grocery stores and convenience stores where fresh foodproduct is displayed in a refrigerated environment. In general,refrigerated merchandisers include a case defining a product displayarea for supporting and displaying food products to be visible andaccessible through an access opening in the case. Some merchandisersinclude doors to enclose the product display area and other refrigeratedmerchandisers are open to the ambient environment. Open refrigeratedmerchandisers utilize one or more air curtains that flow over the accessopening to form a barrier between the refrigerated product display areaand the ambient environment.

Refrigerated merchandisers also typically include one or more shelvesthat are used to support and display the food product. The shelvesextend generally horizontally from a rear wall of the refrigeratedmerchandiser and are arranged vertically relative to one another withinthe display area. Existing refrigerated merchandisers cool food productson the shelves from the rear wall of the merchandiser forward bydischarging cooling air from rear wall apertures. Cooling fans circulatethe cooling air forward.

A particular challenge of open refrigerated merchandisers is maintaininga uniform temperature within the display area. The front of the displayis not only further from the discharged cooling air but is also exposedto warmer ambient air infiltrating the air curtain. Therefore, the frontof the display is warmer than the rear of the display. Current methodsfor homogenizing the temperature within the display area includeincreasing air velocity within the case and additional convectioncooling apparatuses. The current solutions, however, require more energyusage and have variable efficacy depending on product layout andsnowing-up patterns of the evaporator.

SUMMARY

In one aspect, the present invention provides a refrigeratedmerchandiser including a case defining a product display area andincluding an air inlet and an air outlet in communication with theproduct display area to form an air curtain across a front of theproduct display area. The refrigerated merchandiser also includes ashelf that is coupled to the case within the product display area. Theshelf includes insulation between a top and a bottom of the shelf, and apassive heat exchanger that has a heat pipe embedded in the shelf withinthe insulation and that extends from a front of the shelf to a back ofthe shelf. Ambient air infiltrating the air curtain initiates passiveheat transfer within the plurality of heat tubes.

In another aspect, the invention provides a shelf configured to beattached to a merchandiser. The shelf includes a top wall, a front wallcoupled to the top wall, side walls coupled to the front wall and thetop wall, and a bottom wall coupled to the front wall and the sidewallsto enclose a space between the top wall, the front wall, the side walls,and the bottom wall. The shelf also includes insulation disposed in thespace and a passive heat exchanger disposed in the space. The passiveheat exchanger has a heat pipe that is embedded within the insulationand that extends from a front of the shelf to a back of the shelf.Passive heat transfer is configured to be initiated by ambient airinfiltrating the merchandiser.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic cross-section view of a refrigerated merchandiserembodying the present invention and illustrating a plurality of shelves.

FIG. 2 is a schematic perspective view of one of the shelves of FIG. 1including heat pipes.

FIG. 3 is a schematic perspective view of a portion of the shelf of FIG.2 .

FIG. 4 is a front perspective view of the shelf of FIG. 2 supportingfood product and temperature measurement equipment.

FIG. 5 is a graph illustrating surface temperatures associated with theshelf of FIG. 4 .

FIG. 6 is another graph illustrating temperatures associated with foodproduct supported by the shelf of FIG. 4 .

FIG. 7 is a chart illustrating surface temperatures of the shelf of FIG.4 .

FIGS. 8 is another chart illustrating temperatures food productsupported by the shelf of FIG. 4 .

FIG. 9 is a section view of an exemplary heat pipe for the shelf ofFIGS. 2-4 .

Before any embodiments of the application are explained in detail, it isto be understood that the application is not limited in its applicationto the details of construction and the arrangement of components setforth in the following description or illustrated in the followingdrawings. The application is capable of other embodiments and of beingpracticed or of being carried out in various ways.

DETAILED DESCRIPTION

FIG. 1 illustrates a refrigerated merchandiser 10 that may be located ina supermarket or a convenience store for displaying fresh food product14 to consumers. The merchandiser 10 includes a case 18 having a base22, a rear wall 26, sidewalls (not shown), a canopy 30, and a customeraccess opening 34. The rear wall 26, base 22, sidewalls, and canopy 30cooperate to define a partially enclosed product display area 38. Theproduct display area 38 supports the food product 14 in the case 18. Thefood product 14 is displayed on a plurality of shelves 42 within theproduct display area 38. Each shelf 42 projects forward from the rearwall 26 and is accessible through the access opening 34.

In the embodiment of FIG. 1 , the refrigerated merchandiser 10 is anopen-front merchandiser with access opening 34 exposed to an ambientenvironment. In other embodiments, the access opening 34 may be enclosedby one or more doors (e.g., separated by mullions). The merchandiser 10includes a refrigeration system 44 (not entirely shown) that is incommunication with the product display area 38 to provide refrigeratedair (denoted by arrows 48) to the product display area 38. As shown, therefrigeration system 44 includes an evaporator 52 that is disposed in anair passageway 56 of the case 18, a compressor (not shown), and acondenser (not shown) connected in series. Refrigerated airflow 48 exitsthe evaporator 52 and is directed through the air passageway 56 and isdischarged into the display area 38 as an air curtain that maintainsproper temperature conductions for food product 14 on display.

The airflow 48 is discharged through the canopy 30 through an air outlet60 and is directed downward through the product display area 38 towardthe base 22. At least a portion of the airflow 48 is returned to the airpassageway 56 of the refrigeration system 44 via an air inlet 64. Asshown in FIG. 1 , the airflow 48 is drawn into the air passageway 56 bya fan 68 upstream of the evaporator 52. The air inlet 64 is locatedadjacent a bottom end of the display area 38 and the air outlet 60 islocated adjacent a top end of the product display area 38.

With continued reference to FIG. 1 , the rear wall 26 includes an innerpanel 72 that at least partially defines the air passageway 56. Theinner panel 72 includes a plurality of perforations 76 that are incommunication with the air passageway 56. The perforations 76 allow aportion of the airflow 48 to discharge from the air passageway 56 alonga rear portion of the refrigerated merchandiser 10 and into the productdisplay area 38. In some embodiments, the perforations 76 include amatrix of circular openings through the inner panel 72. In otherembodiments, the perforations 76 may be vents that are constructed aselongate (e.g., rectangular) openings through the inner panel 72. Itwill be appreciated that various other shapes, sizes, and arrangementsfor the perforations 76 are also possible in other embodiments.

Referring to FIG. 2 , each of the shelves 42 includes a top wall 80, twosidewalls 84, and a front wall 88. Some or all of the walls 80, 84, 88may be separate pieces that are coupled together, or some or all of thewalls 80, 84, 88 may be formed by bending or shaping a single piece ofmaterial such that edges are defined between the walls (i.e. the wallsare coupled together at the edge). It will be appreciated that two ormore of the walls may be coupled together by insulation 89. In theillustrated embodiment, the top wall 80, the sidewalls 84, and the frontwall 88 cooperate to define an interior volume of the shelf 42. In someembodiments, the walls 80, 84, 88 form a solid shelf 42 (i.e. filledwith insulation 89). With reference to FIGS. 1 and 2 , the shelf 42 iscoupled to the rear wall 26 (e.g., via brackets 90) and projects forwardtoward the front of the merchandiser 10. As shown, the top wall 80projects generally perpendicular from the inner panel 72 and thesidewalls 84 and the front wall 88 extend substantially perpendicular tothe top wall 80. In some embodiments, the shelves 42 may include abottom wall 92.

With reference to FIGS. 2 and 3 , one or more of the shelves 42 includesa passive heat exchanger 100. The illustrated passive heat exchanger 100is formed by one or more thermally conductive heat pipes 102 (e.g., witha thermal conductivity range between 1,000 and 10,000 W/m° K). As shownin FIGS. 2, 3, and 9 , each heat pipe 102 is defined by an elongate tube(e.g., a cylindrical or rectangular prism) that supports a wick 103 anda working fluid 104, and that has a first end 106 positioned at oradjacent the front wall 88 and a second end 110 positioned at oradjacent the inner panel 72. Each heat pipe 102 may be embedded in theshelf 42 and may be coupled to the interior of the shelf via elongategrooves 114 (e.g., defined within insulation 89). The heat pipes 102 canbe secured within the elongate grooves 114 by a press-fit attachment,soldering or welding, thermal epoxies, or any other suitable attachmentmechanism. It will be appreciated that the heat pipes 102 may be coupledto an underside of the top wall 80 without grooves (e.g., adhered orotherwise attached to the top wall 80, sandwiched between the top walland the bottom wall 92, etc.).

The heat pipes 102 are metallic and are vacuumed-sealed. As shown inFIG. 9 , the wick 103 defines a capillary lining that may be fixed tothe inner walls of the heat pipe 102 and may include a metallic material(e.g., sintered copper, screen mesh, grooved metal, etc.). Other wickingmaterials that are suitable for flow of the working fluid 104 throughthe wick 103 may be used in combination with or in lieu of metallicmaterial. The first end 106, which is proximate to the customer accessopening 32 and the front of the shelf 42, defines an evaporator side ofthe heat pipe 102. The second end 110, which is proximate to the innerpanel 72 and the rear of the shelf 42 defines a condenser side of theheat pipe 102.

Referring to FIG. 2 , the passive heat exchanger 100 includes six linearheat pipes 102 that extend between the rear wall of the shelf 42 and thefront wall 88 in a direction that is perpendicular to the front wall 88.The illustrated heat pipes 102 also are parallel to each other. It willbe appreciated that the shelf 42 may have fewer than six heat pipes ormore than six heat pipes. The heat pipes 102 form a one- or two-phaseheat transfer mechanism to transfer infiltrating heat adjacent the frontof the shelf 42 toward the rear of the shelf 42. to maintain moreuniform temperature within the product display area 38, especially inregions adjacent the heat pipe 102 on the shelf 42. The passive heatexchanger 100 limits temperature fluctuations by cooling the portion ofthe shelf 42 adjacent the access opening 34 to reduce or eliminate thewarmer region. This results in a uniform temperature profile across theshelf 42 and a more consistent overall temperature within themerchandiser 10.

The passive heat exchanger 100 can be retrofit into existingmerchandisers (e.g., by replacing existing shelves with shelves 42 thathave the passive heat exchanger 100. Separately or in addition, thepassive heat exchanger 100 may be integrated into different parts of themerchandiser 10 to facilitate even distribution of conditioning airrelative to warm and cold areas within the merchandiser 10. For example,and with reference to FIG. 1 , the merchandiser may include a deck plate134 that partially defines the display area 38 (i.e. a lower boundary ofthe display area 38). The deck plate 134 is positioned above the base 22and, in some embodiments, a passive heat exchanger that is the same asthe passive heat exchanger 100 may be embedded in the deck plate 134(e.g., in an insulation-filled cavity in the deck plate 134).

In operation, refrigerated airflow 48 may be discharged through theplurality of perforations 76 and into the display area 38. In someconstructions, conditioned air may only be distributed to the productdisplay area 38 via the air outlet 60 (e.g., when the merchandiser 10does not include the perforations 76), or in combination with theperforations 76. Ambient air may infiltrate the display area 38 throughthe access opening 34. The ambient air is generally warmer than therefrigerated airflow 48 forming the air curtain 48 at the front of thecustomer access opening 34. The ambient air heats the working fluidwithin the first end 106 of the heat pipe 102. The working fluidvaporizes on the evaporator side and increases pressure within the heatpipe 102. As the pressure increases, the vaporized working fluid flowsrearward via the wick toward the condenser side, proximate the innerpanel 72. At the second end 110, the vaporized working fluid dischargesheat as it is cooled and condensed. The condensed working fluid travelsback toward the warmer first end 106, evenly distributing a coolingeffect within the display area 38.

FIG. 4 illustrates an exemplary refrigerated merchandiser 10 with apassive heat exchanger 100 including a heat pipe 102 that is embedded inthe shelf 42, which supports food product 14. Temperature sensors 118are coupled to the top wall 80 (e.g., in a test environment) to measuretemperatures of the shelf 42 in different locations (e.g., over asection 120 of the shelf 42). For example, and as shown in FIG. 4 , oneor more sensors 118 are positioned on the exterior side of the top wall80 directly over the heat pipe 102, and other sensors 118 are positionedon the top wall 80 opposite sides of the heat pipe 102 (e.g., on a sideto the left of the heat pipe 102 and on a side to the right of the heatpipe 102). The portions of the shelf 102 to the left and the right ofthe heat pipe 102 define left and right test sections of the shelf 42,respectively, and the portion of the shelf 102 that is centered over theheat pipe defines a center test section.

FIG. 5 graphically illustrates an average temperature profile of anexemplary shelf 42 that includes the heat pipe 102 when the evaporator52 has a setpoint of 26° Fahrenheit. FIG. 7 illustrates temperature dataprovided by the sensors 118 in the left test section, the center testsection, and the right test section. As shown, the heat pipe 102maintains a more uniform surface temperature on the shelf 42 (at thecenter) when compared to the left and right test sections that do notinclude a heat pipe. More specifically, and with reference to FIG. 7 ,the average temperature difference or variation on the top wall 80 inthe center test section, from adjacent the front of the shelf 42 toadjacent the inner panel 72, is approximately 2.1° Fahrenheit, whereasthe average temperature differences on the top wall 80 in the left testsection and the right test section (from front-to-back on the top wall80) are approximately 7.4° and 7.3° Fahrenheit, respectively. Statedanother way, the heat pipe 102 decreases the temperature variation onthe top wall 80, on average, from front to back by approximately 70%relative to sections or portions of the shelf 42 without a heat pipe.The second chart in FIG. 7 illustrates the temperature profile of theshelf 42 in the left, center, and right test sections when therefrigeration system 44 is in a defrost mode. As will be appreciated byone of ordinary skill in the art, even during defrost the heat pipe 102maintains a more uniform (e.g., a decrease in temperature variation ofapproximately 58%) and lower overall surface temperature on the shelf 42relative to the sections to the left and right of the heat pipe 102. Thethird chart in FIG. 7 illustrates the temperature profiles of the left,center, and right test sections of the shelf 42 soon after defrost hasbeen terminated (e.g., before frost buildup in the evaporator 52) andshows that the heat pipe 102 maintains a more uniform temperatureprofile from front to back on the shelf 42 than in the left and righttest sections (e.g., a 70% decrease in temperature variation on the topwall 80 from front to back relative to sections or portions of the shelf42 without a heat pipe).

FIGS. 6 and 8 illustrate similar uniformity in the temperaturevariation, from front to back, for food product (tested using foodproduct simulators) that is supported on the shelf 42 over the heat pipe102 and a decrease in temperature variation relative to food productthat is supported on the shelf 42 to the left and right of the foodproduct supported over the heat pipe 102. More specifically, and withreference to FIG. 8 , the average temperature difference or variationfor food product in the center test section, from adjacent the front ofthe shelf 42 to adjacent the inner panel 72, is approximately 5.9°Fahrenheit, whereas the average temperature differences for food productin the left test section and the right test section (from front-to-back)are approximately 8.2° and 8.1° Fahrenheit, respectively. Stated anotherway, the heat pipe 102 decreases the temperature variation of foodproduct, on average, from front to back by approximately 27% relative tofood product on sections or portions of the shelf 42 without a heatpipe. The second chart in FIG. 8 illustrates the temperature profile offood product in the left, center, and right test sections when therefrigeration system 44 is in a defrost mode. Even during defrost, theheat pipe 102 maintains a more uniform (e.g., approximately a 25%decrease in temperature variation) and lower overall temperature of foodproduct relative to the sections to the left and right of the heat pipe102. The third chart in FIG. 8 illustrates the temperature profiles offood product supported in the left, center, and right test sections ofthe shelf 42 soon after defrost has been terminated (e.g., before frostbuildup in the evaporator 52) and shows that the heat pipe 102 maintainsa more uniform temperature profile from front to back on the shelf 42than in the left and right test sections (e.g., a 27% decrease intemperature variation from front to back relative to food product insections or portions of the shelf 42 without a heat pipe).

In some embodiments, the top wall 80 be encapsulated by a shelf coverand may be formed of a material suitable to spread the cooling impact ofthe heat pipe 102 (e.g., metal) toward and at least partially into thesections of the shelf 42 that are adjacent and to the left or right ofthe heat pipe 102. The heat pipe(s) 102 may be embedded in insulation 89to facilitate a more significant and direct impact on the temperature ofthe shelf 42 and food product supported on the shelf 42. Also, by usingseveral heat pipes 102 in a given shelf 42 (and or/in the deck plate134), the heat pipes 102 can be spaced so that sections of the shelf 42between the heat pipes 102 are minimized to avoid less uniformtemperature variations from front to back on the shelf 42. In general,the embedded heat pipe 102 makes the cooling effect predictable andreliable regardless the layout or loading of product on the shelf 42.Existing systems that use an evaporator coil in a shelf cannot achievethe uniformity of temperature, from front to back in the product displayarea 38, associated with the invention described herein.

Various features of the disclosure are set forth in the followingclaims.

1. A refrigerated merchandiser comprising: a case defining a productdisplay area and including an air inlet and an air outlet incommunication with the product display area to form an air curtainacross a front of the product display area; a shelf coupled to the casewithin the product display area, the shelf including insulation betweena top and a bottom of the shelf, the shelf further including a passiveheat exchanger having a heat pipe embedded in the shelf within theinsulation and extending from a front of the shelf to a back of theshelf, wherein ambient air infiltrating the air curtain initiatespassive heat transfer within the plurality of heat tubes.
 2. Therefrigerated merchandiser of claim 1, wherein the heat pipe is a firstheat pipe and the refrigerated merchandiser further includes a deckplate defining a lower boundary of the product display area and having asecond heat pipe.
 3. The refrigerated merchandiser of claim 1, whereinthe heat pipe includes a wick and a working fluid.
 4. The refrigeratedmerchandiser of claim 1, wherein the heat pipe is coupled to an interiorupper wall of the shelf by elongate grooves.
 5. The refrigeratedmerchandiser of claim 4, wherein the heat pipe is secured within theelongate grooves by a press-fit attachment, soldering, welding, or athermal epoxy.
 6. The refrigerated merchandiser of claim 1, wherein theheat pipe is sandwiched between the top and the bottom of the shelf 7.The refrigerated merchandiser of claim 1, wherein the top of the shelfis formed of a material configured to spread a cooling impact of theheat pipe toward and at least partially into a section of the shelfwithout a heat pipe.
 8. A shelf configured to be attached to amerchandiser, the shelf comprising: a top wall; a front wall coupled tothe top wall; side walls coupled to the front wall and the top wall; abottom wall coupled to the front wall and the sidewalls to enclose aspace between the top wall, the front wall, the side walls, and thebottom wall; insulation disposed in the space; and a passive heatexchanger disposed in the space and having a heat pipe embedded withinthe insulation and extending from a front of the shelf to a back of theshelf, wherein passive heat transfer is configured to be initiated byambient air infiltrating the merchandiser.
 9. The shelf of claim 8,wherein the heat pipe includes a wick and a working fluid.
 10. The shelfof claim 8, wherein the heat pipe is coupled to an interior upper wallof the shelf by elongate grooves.
 11. The shelf of claim 10, wherein theheat pipe is secured within the elongate grooves by a press-fitattachment, soldering, welding, or a thermal epoxy.
 12. The shelf ofclaim 8, wherein the heat pipe is sandwiched between the top wall andthe bottom wall.
 13. The shelf of claim 8, wherein the top wall isformed of a material configured to spread a cooling impact of the heatpipe toward and at least partially into a section of the shelf without aheat pipe.